Enforce WARN_UNUSED_RESULT attribute on Windows

components/storage_monitor/test_volume_mount_watcher_win.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // TestVolumeMountWatcherWin implementation.
 
 #include "components/storage_monitor/test_volume_mount_watcher_win.h"
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/storage_monitor/storage_info.h"
 #include "content/public/browser/browser_thread.h"
+#include "testing/gtest/include/gtest/gtest.h"
 
 namespace storage_monitor {
 
 namespace {
 
 base::FilePath GetTempRoot() {
   base::ScopedTempDir temp_dir;
-  temp_dir.CreateUniqueTempDir();
+  EXPECT_TRUE(temp_dir.CreateUniqueTempDir());
   base::FilePath temp_root = temp_dir.path();
   while (temp_root.DirName() != temp_root)
     temp_root = temp_root.DirName();
   return temp_root;
 }
 
 std::vector<base::FilePath> FakeGetSingleAttachedDevice() {
   std::vector<base::FilePath> result;
   result.push_back(VolumeMountWatcherWin::DriveNumberToFilePath(2));  // C
 
@@ skipping 112 matching lines @@
 }
 
 VolumeMountWatcherWin::GetAttachedDevicesCallbackType
   TestVolumeMountWatcherWin::GetAttachedDevicesCallback() const {
   if (attached_devices_fake_)
     return base::Bind(&FakeGetAttachedDevices);
   return base::Bind(&FakeGetSingleAttachedDevice);
 }
 
 }  // namespace storage_monitor